Assembly language

def. a low-level symbolic code converted by an assembler

ex.

> mov a1, 061h :
  load in register a1 the content of memory location of adress 061h

easier to write but codes are extremely long and hard to read and understand

high-level languages

easier to write and read algorithms

> 1972: Dennis Ritchie at Bell telephone
        Labs develops the C language

> 1979: Bjarne Stroustrup at Bell Labs
        design and implement C++
        (C with classes)

More sparse stuff:

• compiler: g++

• command line debugger: gdb

  • not really practical to use

• Integrated Development Environment (IDE)

• ##:

  • single line: //
  • multiple lines: /* ... */

multiple file programs and header files

sparse stuff:

types

operations for variable modification

prefix and postfix

implicit type conversion

ex.

conditional statement

pointer (dereference operator *)

a pointer is a variable that stores the address of another object

• always initialize a pointer, *, with the value zero

• pointers can be assigned addresses of other variables via the address-of operator (ampersand) & - the types of the variable and the pointer have to match

exs.

arrays

what Stroustroup says about:

declaration

• indexes range from 0 to size -1

• to access an element use the subscript operator [] or through a pointer

boundary checking: C/C++ compiler does no boundary check. Using out of range indexes is not detected by compiler and results in computation errors

Sys.time()

## [1] "2018-07-03 18:56:23 +03"